Biggest issues with them from what I have seen. Is because they used lead acid batteries they rust away badly. Where you would expect the engine to be is all battery compartment. I forgot how many deep cycle batteries they use. But, as with all lead acid batteries they give off very corrosive gasses and also will leak. If you don't pull the batteries out and keep after the underside with cleaning and coating they literally crumble away. I would think though if you kept after it, you'd have a pretty handy machine.